PHP Class and Method beginner

Question

I begun to learn PHP Classes & Methods and as a practice exercise I decided to create a Class called Bank Account and trying to implement DisplayBalance(), Withdrawals() and Transaction() Methods.

Most of it works and I am able to display a balance as well as add and subtract 'money' from a account, but what I also want to do is when money is withdrawn beyond the initial balance to remove a balance echo message and replace it with a i.e echo'NO more money'.

At the moment the error message pops up but the balance is also shown. Can someone point me in a right direction please quiet frustrating as i begun to enjoy my experience with classes and methods!

My code:

<?php

class BankAccount{
    public $balance = 10.5;

    public function DisplayBalance(){
        if(($this->balance)<0){
            return false;
        }else{
            return 'Balance: '.$this->balance.'</br>';
        }
    }

    public function Withdraw($amount){

        if (($this->balance)<$amount){
        echo 'Not Enough Founds: '.'</br>';
        }else{
        $this->balance=$this->balance - $amount;
        }
    }

    public function Transaction($trans){
        $this->balance=$this->balance + $trans;
    }
}


$alex = new BankAccount;
$alex->Withdraw(12);
echo $alex->DisplayBalance();

$abdul = new BankAccount;
$abdul->Transaction(10);
echo $abdul->DisplayBalance();

?>

Answer 1

 public function Withdraw($amount){
     $this->balance=$this->balance - $amount;
 }

 public function DisplayBalance(){
    if($this->balance < 0){
        return 'Not Enough Funds: '.'</br>';
    }else{
        return 'Balance: '.$this->balance.'</br>';
    }
  }

or you can try this one

class BankAccount{
  public $balance = 10.5;
  public $error = false;

  public function DisplayBalance(){
    if($this->error){
        $this->error = false;
        return 'Not Enough Funds: '.'</br>';
    }else{
        return 'Balance: '.$this->balance.'</br>';
    }
  }

  public function Withdraw($amount){

     if (($this->balance)<$amount){
       $this->error = true;
     }else{
       $this->balance=$this->balance - $amount;
     }
 }
}
$alex = new BankAccount;
$alex->Withdraw(12);
echo $alex->DisplayBalance();

Answer 2

You're doing withdraw(12) first, and this is what happens:

 if (($this->balance)<$amount){
    echo 'Not Enough Founds: '.'</br>';

And that's it, no substraction is executed. Then you do display():

public function DisplayBalance(){
    if(($this->balance)<0){
        return false;
    }else{
        return 'Balance: '.$this->balance.'</br>';
    }
}

Well, $this->balance is still 10.5 as in previous function you've just echoed an error and haven't made any $this->balance - $arg. Try fixing it like this:

public function Withdraw($amount){

    if (($this->balance)<$amount){
      // $this->balance=0; you can zero your balance out
      // $this->balance -= $amount; or just make it -1.5 so display() function would
      // do its job
      echo 'Not Enough Funds: '.'</br>';
    }else{ 
      $this->balance=$this->balance - $amount;
    }
}